<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>留言板</title>
    <style>
        .container {
            width: 350px;
            height: 300px;
            margin: 0 auto;
            /* border: 1px black solid; */
            text-align: center;
        }

        .grey {
            color: grey;
        }

        .container .row {
            width: 350px;
            height: 40px;

            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .container .row input {
            width: 260px;
            height: 30px;
        }

        #submit {
            width: 350px;
            height: 40px;
            background-color: orange;
            color: white;
            border: none;
            margin: 10px;
            border-radius: 5px;
            font-size: 20px;
        }
    </style>
</head>

<body>
    <div class="container">
        <h1>留言板</h1>
        <p class="grey">输入后点击提交, 会将信息显示下方空白处</p>
        <div class="row">
            <span>谁:</span> <input type="text" name="" id="from">
        </div>
        <div class="row">
            <span>对谁:</span> <input type="text" name="" id="to">
        </div>
        <div class="row">
            <span>说什么:</span> <input type="text" name="" id="say">
        </div>
        <input type="button" value="提交" id="submit" onclick="submit()">
        <!-- <div>A 对 B 说: hello</div> -->
    </div>

    <script src="js/jquery.main.js"></script>
    <script>
        $.ajax({
            type: "get",
            url: "/message/getList",
            success: function (messages) {
                //如果后端返回的是 JSON类型 前端可以直接作为对象来进行使用
                //如果后端返回的是 html类型 前端必须要把他转换为对象来使用
                if (messages != null) {
                    for (var message of messages) {
                        var divE = "<div>" + message.from + "对" + message.to + "说" + message.msg + "</div>";
                        $(".container").append(divE);
                    }
                }
            }
        });


        function submit() {
            //1. 获取留言的内容
            var from = $('#from').val();
            var to = $('#to').val();
            var say = $('#say').val();
            if (from == '' || to == '' || say == '') {
                return;
            }
            //如果不为空
            //调用后端接口，发表留言
            $.ajax({
                type: "post",
                url: "/message/publish",
                data: JSON.stringify({
                    "from": from,
                    "to": to,
                    "msg": say
                }),
                contentType: "application/json",
                success: function (result) {
                    if (result) {
                        //成功
                        //2. 构造节点
                        var divE = "<div>" + from + "对" + to + "说:" + say + "</div>";
                        //3. 把节点添加到页面上    
                        $(".container").append(divE);

                        //4. 清空输入框的值
                        $('#from').val("");
                        $('#to').val("");
                        $('#say').val("");
                    } else {
                        //失败
                        alert("发布失败！！！");
                    }
                }
            });





        }

    </script>
</body>

</html>